Device for a temperature-regulated cabinet

ABSTRACT

A temperature-regulated cabinet ( 1 ) comprising a commodity compartment ( 8 ) having at least one closable opening ( 12 ), and also at least one air-temperature-regulating and flow-promoting means ( 20 ), in which at least one supply conduit ( 22 ) extends from the air-temperature-regulating and flow-promoting means ( 20 ) and onwards to at least one inflow distributor ( 24 ), the inflow distributor ( 24 ) communicating with the commodity compartment ( 8 ), and in which at least one discharge conduit ( 32 ) extends from the commodity compartment ( 8 ) and onwards to the air-temperature-regulating and flow-promoting means ( 20 ), and wherein at least one discharge distributor ( 28 ) is arranged between the commodity compartment ( 8 ) and the discharge conduit ( 32 ), the flow area of the discharge distributor ( 28 ) being smaller than the flow area of the inflow distributor ( 24 ).

This invention concerns a temperature-regulated cabinet. More particularly, it concerns a temperature-regulated cabinet comprising a commodity compartment having at least one closable opening, and also air-temperature-regulating and flow-promoting means, in which at least one supply conduit extends from the air-temperature-regulating means and onwards to at least one air inflow distributor, the inflow distributor communicating with the commodity compartment. Preferably, the flow area of the inflow distributor is smaller than the cross-sectional area of the supply conduit. At least one discharge conduit extends from the commodity compartment and onwards to the air-temperature-regulating means. At least one discharge distributor is arranged between the commodity compartment and the discharge conduit, the flow area of the discharge distributor being smaller than the flow area of the inflow distributor.

Prior art temperature-regulated cabinets exhibit a relatively large temperature variation in the commodity compartment during normal operation. Upon opening e.g. a door in the cabinet, the temperature is altered significantly at least in parts of the cabinet, and several tens of minutes may lapse after closing the door before the temperature in the cabinet stabilizes at a desired level.

Upon preparing e.g. biological samples, an even temperature is vital for the result and reliability of the sample. The samples may be destroyed due to the temperature change arising when the cabinet door is opened in prior art cabinets.

It is known to seek to distribute the air entering into the commodity compartment in order to reduce the temperature differences in the cabinet. Document EP 1588650 thus concerns a cabinet for a vending machine provided with an inflow distributor in the form of a perforated plate. An inlet port located upstream of the inflow distributor is provided with a larger cross section than the flow area of the inflow distributor. An overpressure is thus formed in the supply conduit. According to the document, the overpressure contributes to direct the inflowing air in the desired direction. The inflow distributor according to EP 1588650 is assigned a dissimilar opening pattern in order to obtain a suitable air distribution in the cabinet. The relative number of openings increases with the distance from the inlet port, indicating that the overpressure in the supply conduit does not have a distributing function.

The object of the invention is to remedy or reduce at least one of the disadvantages of the prior art.

The object is achieved in accordance with the invention and by means of features disclosed in the following description and in the subsequent claims.

A temperature-regulated cabinet in accordance with the invention comprises a commodity compartment having at least one closable opening, and also air-temperature-regulating and flow-promoting means, in which at least one supply conduit extends from the air-temperature-regulating means and onwards to at least one inflow distributor, the inflow distributor communicating with the commodity compartment. Preferably, the flow area of the inflow distributor is smaller than the cross-sectional area of the supply conduit. At least one discharge conduit extends from the commodity compartment and onwards to the air-temperature-regulating means. The cabinet in accordance with the invention is characterized in that at least one discharge distributor is arranged between the commodity compartment and the discharge conduit, the flow area of the discharge distributor being smaller than the flow area of the inflow distributor.

Advantageously, the inflow distributor may form at least a portion of at least one of the walls of the commodity compartment, whereas the discharge distributor advantageously also may form at least a portion of at least one of the walls of the commodity compartment. In this context, the term walls also comprise the at least one door, ceiling and bottom of the cabinet.

The relative positioning of the inflow- and discharge distributors is selected so as to achieve an approximately equal flow velocity in the commodity compartment. The inflow- and discharge distributors may be divided and distributed in dissimilar regions of the commodity compartment.

Typically, the flow area of the inflow distributor is 2 to 50% smaller than the cross-sectional area of the supply conduit.

More advantageously, the flow area of the inflow distributor is 4 to 30% smaller than the cross-sectional area of the supply conduit.

Most advantageously, the flow area of the inflow distributor is 6 to 15% smaller than the cross-sectional area of the supply conduit.

Typically, the flow area of the discharge distributor is 2 to 50% smaller than the flow area of the inflow distributor.

More advantageously, the flow area of the discharge distributor is 4 to 30% smaller than the flow area of the inflow distributor.

More advantageously, the flow area of the discharge distributor is 6 to 15% smaller than the flow area of the inflow distributor.

The ratio between the flow area of the inflow distributor relative to the cross-sectional area of the supply conduit, and the flow area of the discharge distributor relative to the flow area of the inflow distributor, may be dissimilar in dissimilar parts of the commodity compartment.

The air-temperature-regulating means is comprised of at least a cooling- or a heating element, whereas the flow-promoting means typically is comprised of a fan which, besides being able to supply air via the discharge conduit, also is formed in a manner allowing it to supply air from the surroundings via a supply opening.

By selecting a sufficiently large fan capacity and selecting the inflow distributor flow area in accordance with said values relative to the cross sectional area of the supply conduit, an overpressure arises in the supply conduit, the overpressure causing the flow velocity through the inflow distributor openings to be approximately equal and substantially independent of the distance from the flow-promoting means. This ensures an even inflow of air across the entire area of the inflow distributor.

The relative ratio between the smaller flow area of the discharge distributor and the larger flow area of the inflow distributor causes an overpressure to arise relative to the surroundings in the commodity compartment.

When the cabinet door is opened, temperature-regulated air thereby discharges from the cabinet, whereas new air, which is admitted via the supply opening and further through the air-temperature-regulating and flow-promoting means, is supplied via the inflow distributor. A substantially unaltered temperature is thus maintained in the cabinet, even when the door is opened.

Calculations have shown that the temperature variation in a temperature-regulated cabinet in accordance with the invention may approach as little as 1° C., even when a door is opened.

It may be necessary to provide e.g. the supply conduit with a closable opening facing the outside of the cabinet for allowing a relatively speedy draining of e.g. air, which may have an excessively high temperature, from the cabinet.

The cabinet is suitable for regulation of the internal atmosphere, for example with respect to gas composition and moisture.

In the following, an example of a preferred embodiment is described and depicted in the accompanying drawings, in which:

FIG. 1 shows, in perspective, a cabinet in accordance with the invention;

FIG. 2 shows a vertical section taken along line Ia-Ia in FIG. 1;

FIG. 3 shows horizontal section taken along line Ib-Ib in FIG. 1, but with a closed door; and

FIG. 4 shows horizontal section taken along line Ib-Ib in FIG. 1.

In the drawings, reference numeral 1 denotes a temperature-regulated cabinet, hereinafter denoted cabinet, comprising four external walls 2, a top surface 4 and a base plate 6. The cabinet 1 is provided with a commodity compartment 8 partitioned by means of shelves 10. One of the external walls 2 is provided with a closable opening 12 to be closed by means of a sealing door 14.

A supply opening 16, which is located below the door 14, allows air to enter from the outside and into a base 18 of the cabinet 1, preferably via a filter (not shown).

A fan 20 comprising a heating element with necessary controls (not shown), hereinafter denoted cabinet, forms the temperature-regulating and flow-promoting means of the cabinet 1.

At the back of the cabinet 1, a supply conduit 22, see FIG. 2, extends from the fan 20 and is separated from the commodity compartment 8 by means of an inflow distributor 24 in the form of a perforated plate.

First perforations 26 of the inflow distributor 24 are furnished with a total flow area being smaller than the flow area of the supply conduit 22, said first perforations 26 being distributed approximately evenly across the back of the commodity compartment 8.

During operation, an overpressure relative to the commodity compartment 8 will thus build up in the supply conduit 22, which contributes to the air flowing with an approximately equal flow velocity through the first perforations 26.

Closest to the closable opening 12, both side walls of the commodity compartment 8 are provided each with a discharge distributor 28 in the form of a perforated plate. Second perforations 30 of the discharge distributors 26 have a total flow area being smaller than the flow area of the first perforations 26.

Air discharges from the discharge distributors 26 via a discharge conduit 32 each, through openings 34 in the base 18 and back to the fan 20.

Due to the larger flow area of the first perforations 26 relative to the second perforations 30, an overpressure arises in the commodity compartment 8 during operation, also with respect to the discharge conduits 32. This overpressure causes the discharge velocity through the second perforations 30 of the discharge distributors 28 to be approximately equal.

As a result, the air flow through the commodity compartment 8 is even and approximately equal at all levels of height. The flow is indicated with arrows in FIG. 3.

When the door 14 is opened, see FIG. 4, the air no longer discharges from the commodity compartment 8 through the discharge distributors 28, but out through the closable opening 12. By virtue of the air flow through the inflow distributor 24 still ensuring an even air flow through the commodity compartment 8, as indicated with arrows in FIG. 4, an even temperature is maintained in the commodity compartment 8, even if the door is opened. Required air for the fan 20 is admitted through the-supply opening 16. 

1. A temperature-regulated cabinet comprising a commodity compartment having at least one closable opening, and also at least one air-temperature-regulating and flow-promoting means (20), in which at least one supply conduit extends from the air-temperature-regulating and flow-promoting means and onwards to at least one inflow distributor, the inflow distributor communicating with the commodity compartment, and in which at least one discharge conduit extends from the commodity compartment and onwards to the air-temperature-regulating and flow-promoting means characterized in that at least one discharge distributor is arranged between the commodity compartment and the discharge conduit, the flow area of the discharge distributor being smaller than the flow area of the inflow distributor.
 2. The temperature-regulated cabinet according to claim 1, characterized in that the inflow distributor forms at least a portion of at least one of the walls of the commodity compartment.
 3. The temperature-regulated cabinet according to claim 1, characterized in that the discharge distributor forms at least a portion of at least one of the walls of the commodity compartment.
 4. The temperature-regulated cabinet according to claim 1, characterized in that the inflow- and discharge distributors are divided and distributed in dissimilar regions of the commodity compartment.
 5. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the inflow distributor is between 2 and 50% smaller than the cross-sectional area of the supply conduit.
 6. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the inflow distributor is between 4 and 30% smaller than the cross-sectional area of the supply conduit.
 7. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the inflow distributor is between 6 and 15% smaller than the cross-sectional area of the supply conduit.
 8. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the discharge distributor is between 2 and 50% smaller than the flow area of the inflow distributor.
 9. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the discharge distributor is between 4 and 35% smaller than the flow area of the inflow distributor.
 10. The temperature-regulated cabinet according to claim 1, characterized in that the flow area of the discharge distributor is between 6 and 15% smaller than the flow area of the inflow distributor.
 11. The temperature-regulated cabinet according to claim 1, characterized in that the relative ratios between the flow area of the inflow distributor relative to the cross-sectional area of the supply conduit, and the flow area of the discharge distributor relative to the flow area of the inflow distributor, are dissimilar in dissimilar parts of the commodity compartment. 